Cannot save Level.sav

[FlorentP42]

So I managed to open and edit Level.sav with Firefox... Sadly when I try to save it, nothing happens (no popup to ask for save location, no automatic save in Downloads folder, am I looking at the wrong location?)... The save button just stays highlighted and that's is.

Any clue what could go wrong here?

Here is the file infos (size):

It took around 15s to open so I assume it should take around the same time to export. Is there any reason that would make it take longer?

EDIT: Well I tried one more time and got it to work that time... Not sure what happened the first time... Does the website prevent saving if some values are out of bounds maybe? (I may have entered a too large number for an inventory stack the first time).

Also the inventory edit did not work, I guess there must be some hash cross-check somewhere? The game asked me to create a new character when I tried to load the save with the edited inventory slot :/